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(MOdeL) 2 Sheets- Sheet 1. M. ATTWOOD & H. R. TAYLOR. GHEMISTS,ASSAYERS, AND PROSPEGTORS BALANCE. No. 357,139.

f/jf, 1 Patented Feb. 1, 1887.

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2 Sheets-Sheet 2.

M. ATTWOOD & H. R. TAYLOR. GHEMISTS, ASSAYERS, AND PRO$PEGTORS BALANCE.

Witnesses. Inventors N. PKYERS PhnlmLmmgmpb-n wnsdn rm D (l ing theglass case and swinging foot.

' UNITED STATES PATENT OFFICE.

MELVILLE ATTWOOD, OF SAUOELITO, AND HENRY TAYLOR, OF OAK- LAND,CALIFORNIA; SAID ATTWOOD ASSIGNOR TO SAID TAYLOR.

CHEMISTS, ASSAYERS, AND PROSPECTORS BALANCE.

SPECIFICATION forming part of Letters Patent No. 357,139, dated February1, 1887.

Application filed September 15, 1885. Serial No.177,l08. (Modch) To allwhom. it 11mg concern:

Be it known that we, MELVILLE ATTWOOD, residing at Saucelito, Marincounty, California,and a subject of the Queen of Great Britain, c andHENRY R. TAYLOR, residing at Oakland,

Alameda county, State of California,and a citizen oftheUnited States,haveinvented new and useful Improvements in Balances, of which this is aspecification.

The object of our invention is to produce a small, reliable, convenient,and cheap balance for any light weighing, but more especially forchemists, assayers, and prospectors; and

for a more thorough understanding thereof reference is had to theaccompanying drawings, in which- Figure 1 is a side elevation showingthe beam resting upon the lifters with the knifeedges raised oil thecenter bearings. Fig. 2 is a plan view. Fig. 3 shows the same with thebeam resting upon the knife-edges on the center bearings. Fig. 4 is adetail. Fig. 5 is a transverse elevation of the balance, showing an endview of the same mounted for use, also show- Figs. 6 and 7 are anelevation and a plan of the same packed ready to go into its case, asshown in Fig. 11. Fig. Sis a detail,to be hereinafter explained. Fig. 9is a rubber wad, and Fig. 10 shows a small vial of weights. Fig. 11shows a tin or leather case of sufiicient size to hold the scale withall its appurtenances when not in use or for transportation.

Similar letters indicate corresponding parts 5 throughout the severalviews.

A is a block of wood, upon which are mounted and permanently fastenedthe two bearings 13 B, the tops of which are provided with anysufiiciently hard material to resist the cutting action of theknife-edges O O. In the present case we employ glass rods D D. To and atright angle, with the knife-edge bearing 0 O is secured a light anddelicately-balanced beam, E, on one end of which is suspended by athread a small scale-pan, F, and by its weight the beam is brought intoequilibrium. For finer adjustments the adj ustingcounterpoise orfeather-adjustment G, which turns upon the stud H, is used. This is anold so device and used by nearly all scale-makers.

The beam is made of any very thin metal in the form of a letter T,having a rib,L,on the under side to strengthen it. The scale-pan issuspended from one end at E, while the other end serves as apointer topass over the graduated scale M, the wide end of which may be graduatedinto ten or more equal parts or divisions; and for the purpose ofillustration we will assume that there are ten. Consequently,if theweight I equals one grain and is placed upon the seventh graduation fromthe center it will require seven-tenths of a grain in the pan to balanceit. Two or more weights may be used at a time of different sizes wheneX- treme accuracy is desired. These weights may be round or flat; ifround, the graduations should be as wide and deep as possible, toprevent their'rolling.

The two lifters J J, operated by the eccentric knob K, are raised toreceive the beam, they being provided with arms reaching under thebeam,having in each a V-shaped notch to receive the rib L on the underside of the beam. In this position the pan may be put on or removed, theweights changed, and the article to be weighed manipulated at thepleasure of the operator, who,when he desires, turns the eccentric knob,gently drops the beam until it rests upon the knife-edges on the glassbearings,when the pointer end will at once-indicate upon the scale M theweight of the article, as shown in Fig. 3.

In order to secure a level position (which is important) the block Aisprovided with two thumb-screws, N N, and the swinging foot 0,andcircular level P, which levels in all directions at once, and also toprevent motion endwise to the beam the knife-edge passes through theforked guide Q. (Shown in broken lines in Figs. 3 and 6; also, in plan,Figs. 2 and 7; also, in detail in Figs. 4 and S.) This guide has itscenter of motion in the pin R, and is raised and lowered by a pin, S, inthe end of the eccentric-knob shaft. Said pin passes through the slottedhole T, and it will be observed that as the beam is lowered the guide isalso brought down, but faster than the beam, so that when theknife-edges touch the glass bearings the bottom of the V-shaped notcheson the guide is someways below them, thus preventing any friction thatwould result by the knife-edges touching and resting upon the bottom ofsaid notches. This slot T is seen in Fig. 3, the eccentric knob beingomitted for that purpose.

The end pieces, U U, of wood, are secured to the block A by the dowelsV, fixed firmly into it, but fit snugly in the uprights. These pieceshave grooves XV, into which the glass plates X are slid, as shown inFig. 2, and also one plate X is laid on top, as shown in Fig. 1, thusforming a glass case, which will completely shelter the balance from theslightest breath of air. The scale M is dovetailed into one of these endpieces, and can be removed and placed in the hole Z, shown under the panwhen the apparatus is packed, as shown in Figs. 6 and 7.

The transverse section, Fig. 8, is through a and 1), Figs. 1 and 2. Itshows the eccentric knob and mode of operating the two lifters J J andthe forked guide Q. The short end 0 c of lifters J J are confinedbetween the two springs d d, with the eccentric part of theknob restingupon the top one; and it will be seen that by depressing it the lowerone must also be forced downward and the forked guide Q is carriedupward.

The slot 0 in Figs. 1, 3, and 6 is for the purpose of holding thetweezers f. (Shown in Figs. 6 and 7.) The holes gand h in Figs. 1, 3,and 6 are for the purpose of holding the cocentric knob and the smallvial of weights, the latter being shown in Fig. 10.

In order to pack the apparatus in the least possible space fortransportation, the three pieces of glass X, which are of equal length,breadth, and thickness, are withdrawn from their respective slots andplaced below the block A, as shown in Fig. 6. The pan and scale areremoved and placed in the hole Z and covered by the rubber wad, Fig. 9.The lifters J J with the forked guide Q, are lowered, and the beam Eremoved and placed on top of the block A, which contains a groove deepenough to accommodate the rib on the under side of the beam, and issecured by the button '2'. The two end pieces, U, are then laid withtheir slotted sides up, the dowels V entering the holesj, and theswinging foot 0 is swung back into the recess 7; in the side of theblock A, Fig. 5. The tweezers are putin the slotf,

the vial of weights, Fig. 10, and the eccentric knob in their respectiveholes 5 h in the block A, as shown in Figs. 6 and 7, when the whole isslid into the case, (represented in Fig. 11,) which can be easilycarried in the pocket.

From the foregoing it will be seen that we have invented anew and usefulbalance that will for its completeness and low cost be desirous to many,and the only attempt made,

to our knowledge, to supply the demand was by Dr. Black, whose balancewas composed of a simple strip of wood suspended by a needle, withoutpan, lifters, guide, or glass case. Such an instrument is illustrated inMakins Metallurgy, page 288.

Having illustrated and described our invention, what we claim as new,and desire to secure by Letters Patent of the United States, is-

1. The combination of a metallic beam having a T-shaped sectionequipoised by the scalepan suspended from one end,and thefeatheradjustment, said beam resting upon central bearings fixed toablock, in combination with the two lifters operated by the eccentricknob 7 5 and springs, substantially as set forth.

2. The combination of a metallic beam haviuga T-shaped sectionequipoiscd by the scalepan suspended from one end, and thefeatheradjustment, said beam resting upon central 8o bearings fixed to ablock having two lifters operated by the eceentricknob and springs, incombination with the two thumb-screws, a swinging foot serving as feet,and a circular level, substantially as described.

3. The combination of a metallic beam having a T-shaped section balancedby a scale-pan suspended from one end and the feather-adjustment, saidbeam resting upon central bearings fixed to a block having two liftersoperated by an eccentric knob and springs, also two thumb-screws, aswinging foot serving as feet, and circular level, in combination with aforked guide to counteract end motion, said guide being operated by apin in the end of the eccentric-knob shaft, substantially as herein setforth.

4. The combination of a metallic beam having a T-shaped section balancedbya scale-pan suspended from one end, and a feather-adjust- IOO ment,saidbeam resting upon central bearings fixed to a block having twolifters operated by an eccentric knob and springs, also two thumbscrews,a swinging foot serving as feet, and circular level, also a forked guideoperated m5 by a pin in the end of aneccentric-knob shaft, incombination with a glass and wooden case or housing having a graduatedscale, substantially as described.

MELVILLE ATTWOOD. HENRY R. TAYLOR.

\Vitnesses J. F. KINGWELL, Orrs H. SAWYER.

